The invention is based on a priority application EP04291578.5 which is hereby incorporated by reference.
The present invention concerns the field of the telecommunications, more particularly in relation to services available through mobile terminals connectable to communication networks.
The present invention concerns more specifically a method and a system allowing to provide streaming data transmission, and associated services, to a mobile terminal, in particular from a streaming server.
In a discontinuous coverage network (also known as “info-station” system), downstream data flows (necessary to provide certain services at a mobile terminal) are managed and handled by taking into account the specific nature of the connection.
Thus, when a streaming service is considered, it would mean that the streaming server must have the ability to deliver discontinuously the data in a different manner for each mobile terminal according to its particular situation.
In fact, legacy streaming servers deliver the data regularly, at the bit rate of the media and not more. This is actually generally mandatory, among others for multicast sessions like “time staggered” or “live event” sessions. As a matter of fact, in such multicast sessions, the server cannot adapt its behaviour to a particular user.
The RTP (Real-time Transport Protocol) standard has defined a “translator function” which takes in charge the “per-user customisation” of the source coding, in the purpose of adapting the throughput of the data flow for a specific user depending on the bandwidth he/she can rely on.
Nevertheless, this known function does not handle the discontinuous aspect of the user's connectivity, and its impact on the provided quality and continuity of service.
It is a main aim of the present invention to overcome the aforesaid drawbacks and restrictions of the prior art.
To this end, the present invention concerns first a method for providing a transmission link, adapted for a streaming data traffic, to a mobile terminal connected to a discontinuous coverage network, characterised in that said method comprises the steps of:                providing a proxy equipment comprising cache or buffer means for receiving and storing at said equipment streaming data intended for said mobile terminal,        establishing a streaming connection or session between said proxy equipment and said mobile terminal, upon request of a service from said terminal requiring streaming data,        forwarding streaming data from said proxy equipment to said mobile terminal when this latter is detected to be under the coverage of and/or connected to said discontinuous coverage network.        
According to a main feature of the invention, when the request for a service requiring streaming data sent by the mobile terminal is received by the proxy equipment, this latter establishes a continuous data and signalling transmission link with the server providing the requested service and a discontinuous data transmission link with said mobile terminal.